1. Field of the Invention
The field of the present invention is dental cosmetics, and more specifically the cosmetic whitening of teeth through photochemical processes.
2. Background
Teeth whitening processes have quickly become some of the most sought after cosmetic dental procedures by many individuals. The popularity appears to stem from the self esteem people obtain from having classic, pearly white teeth which are free from stains that result from drinking beverages such as coffee or tea, eating foods containing dyes, or smoking.
Teeth whitening procedures may be performed at a dental office or in the comfort of one""s own home. The in-office procedures usually achieve better results, in a much shorter amount of time, than at home procedures. However, the in-office procedures are often expensive and lengthy, as they may cost approximately $500 or more and may require the patient to sit in the dentist""s chair for over an hour with an open mouth while the procedure is performed. One example of an in-office procedure is disclosed in U.S. Pat. No. 5,713,738. In that procedure, the patient""s mouth is first prepared so that only the teeth are exposed and the gums are protected. Then, an oxidizing bleaching solution is applied to the teeth and the teeth are exposed one at a time to light from an argon laser. Further bleaching is possible by applying a second bleaching solution and exposing the teeth to light from a carbon dioxide laser. This entire process can be time consuming, and therefore expensive.
A second in-office procedure is disclosed in U.S. Pat. No. 6,162,055. For this procedure, a photosensitizing agent is first applied to the teeth followed by an oxidizing bleaching solution. The teeth are then exposed to light in the visible spectrum to activate the photosensitizer and the bleaching solution, thus accelerating the bleaching process. The light of this procedure is limited to visible light because of the potential harmful effects of UV and infrared radiation to the teeth and gums. This procedure tends to take less time than the procedure described in the ""738 patent. However, as with any visit to the dental office, it may be a costly cosmetic procedure. Thus, for many individuals, the requirements of in-office teeth whitening procedures present too great of an inconvenience, leaving a desire for alternative teeth whitening processes.
Home teeth whitening procedures may be favored over the in-office procedures because they enable teeth whitening in the comfort and convenience of one""s own home. However, the currently available home products have their own limitations. Teeth whitening at home may be performed through the use of whitening tooth pastes. However, whitening toothpastes often yield unsatisfying results because they are often not effective on harsh stains and they must be used for extended periods of time to achieve noticeable results.
Other at home processes have thus been developed in an attempt to increase the whitening obtainable through home processes and decrease the time it takes to achieve noticeable results. These more recent processes frequently require a tray, the tray being either a generic tray, such as the one described in U.S. Pat. No. 6,089,869, or a plastic strip, such as the one described in U.S. Pat. No. 5,879,691, to be placed in the mouth for an hour or more at a time. The tray or plastic strip includes a bleaching solution, and while the tray is worn, the teeth are slowly whitened. The whitening process typically takes a period of weeks.
One drawback of these home teeth whitening devices is that they may interfere with normal daily activity if worn during the daytime. Therefore, the devices are frequently worn only at night while sleeping. However, for some even having to wear such devices at night presents an inconvenience. An additional drawback of these home devices is that the whitening achieved tends to be less significant than the in-office procedures.
The present invention is directed to a light-emitting toothbrush and a method of whitening teeth. The toothbrush comprises a head having bristles affixed to a first side, a handle affixed to a second side of the head, a light source, and a light guide having a first end disposed within the head and a second end optically coupled to the light source. The light source emits light in a spectrum ranging from about 350 nanometers to about 700 nanometers, although narrower spectra may also be used. The light guide is formed and positioned so that light entering the second end of the light guide is guided to the first end and directed out of the first side of the head. Thus, when teeth are brushed using the toothbrush, light emitted from the head is directed towards the teeth.
The light source may be disposed within the handle or external to the handle. For an external light source, the light source may be optically coupled to the waveguide using an optical fiber. A band pass filter may be included with the light source so that only light within the desired spectrum passes into the waveguide.
The method of the present invention is directed to a process for whitening teeth. A bleaching solution is first applied to the teeth or to the bristles of a toothbrush, followed by generating light in a spectrum ranging from about 350 nm to about 700 nm. The generated light is guided out of the side of the toothbrush to which the bristles are affixed. Teeth may then be brushed to gain the benefits of photo-bleaching to whitening the teeth. The bleaching solution includes an oxidizer selected from the group consisting of carbamide peroxide, carbamyl peroxide, sodium percarbonate, perhydrol urea, peroxyacetic acid, and hydrogen peroxide.
Accordingly, it is an object of the present invention to provide a light-emitting toothbrush and a method of whitening teeth. Other objects and advantages will appear hereinafter.